<!DOCTYPE html>
<html lang="en">
<head>
    <title>Bootstrap</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-wdith,initial-scale=1.0">
    <link href="css/bootstrap.css" rel="stylesheet">

    <!-- IE9兼容 -->
    <!-- [if llt IE 9]>
        <script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
    <![endif] -->

    <!-- 背景根据窗口自适应 -->
    <style>
        body{background: dodgerblue;}
        @media(min-width: 600px) and (max-width: 1200px){body{background: white;}}
    </style>
</head>
<body>

    <h1 class="visible-lg">电脑显示visible-lg</h1>
    <h1 class="visible-md">平板显示visible-md</h1>
    <h1 class="visible-xs">手机显示visible-xs</h1>

    <script src="js/jquery-3.1.1.js"></script>
    <script src="js/bootstrap.js"></script>
</body>
</html>